Ropeless elevator systems, also referred to as self-propelled elevator systems, are useful in certain applications (e.g., high rise buildings) where the mass of the ropes for a roped system is prohibitive and there is a desire for multiple elevator cars to travel in a single lane. There exist ropeless elevator systems in which a first lane is designated for upward traveling elevator cars and a second lane is designated for downward traveling elevator cars with at least two transfer stations in the hoistway used to move cars horizontally between the first lane and second lane.
Transfer stations do not typically provide redundancy for transfer station operation. Therefore, the numbers of structures capable of moving elevator cars is equal to or lower than the number of lanes of the hoistway. The assumption is that in a worst case scenario, independent working carriages in the transfer station may work with a reduced number of carriages. Working with a reduced number of carriages decreases overall elevator system efficiency and may cause operation delays, as well as logistical challenges.